Vulcanizing apparatus



Patented Oct. 21, 1952 VULCANIZING APPARATUS Peter J I ,Mamola,'Astoria,N..Y., assignor to Western Electric Company, Incorporated, New York,N.Y., a corporation ofNew York Application July 19, 1950,Serial No.174,635

' 10 Claims. 1

This inventionhrelates. to vulcanizing apparatus and more particularlyto an indicating and control circuit for electrically heatedvulcanizers.

In vulcanizing. apparatus, it is necessary to subject the article beingvulcanized to a predetermined amount of heat, after which the heatsource must be disconnected and the article allowed to cure beforebeingexposed to the atmoshphere.

Itis an object of thisinvention to providenew and improved means forautomatically deter- .mining andindicating the vulcanizing. and ouringcycles during a vulcanizing operation.

In accordance with a preferred embodiment of the invention, anelectrically heated mold is provided wherein the power circuit theretois so connected thr ugh -a double-contact circuit sponsive element andresistance in. parallel with the resistance heating elements in one ofthe mold sections, in such. a manner that-the thermal element will closewhenthe temperature in the mold reaches a predetermined maximum value.This action results in a lowered effective resistance, and thus a highercurrent flow through the circuit breaker, therebycausing thebreakerv totripto its-second set of contacts.

A more complete understanding of the invention may be had by. referringto. the following detailed description,-when read in conjunction withthe accompanying single figure drawing which schematically represents a,vulcanizing mold and a circuit for controlling-the heating of the mold.in accordance with the invention.

:The'apparatus consists of a lower fixed mold section having a lower.mold cavity H, and an upper movable mold'section l2 having an upper moldcavity I3. The upper mold cavity 13 "is adaptedto be moved into registerwith the =lower7moldcavity l l :by means. of ahingeduconnection l4, andsuch movement} results .in the closure of a normally'open microswitch Iwhich initiates energization .of electrical heating elements carried bythe two moldsections.

.For the purpose of heating the mold sections a pairlof resistanceheatingielements'i'l)and 21 F are provided, which elements aredisposedin rthermal relationship with,-but electrically insulated from,the upper and' lower mold sections Willand l 2rrespectively..The;heatingelements:2G sand 3.2l are preferably :::connected in.parallel across a source of current 22 with one side of the parallelconnection being completed directly to the source 22. The other side ofthe parallel connected heating elements is adapted to be connected tothesource 22 through an actuating .coil 23 ofa single pole double throwcircuitbreaker .24. provided withtalternate fixed contacts 25 and 26 anda movablecontact 21. The circuit through .thecoil 23 to thesource 22 iscompleted Zlthen remains incontact with contact 26 until it, is manuallyreset.

Inorder to determine theamount of heat which is applied to theyarticlebeing vulcanized in the cavities-ll and [3, an inverse'thermoswitch 30is provided, which thermoswitch is characterized by'its :ability toprovide a closed electrical circuit when the temperature thereof reachesa predetermined maximum value. vThe thermoswitch 30 may be mounted inthermalrelation :with either .one of themold sections H1 or l2,..and;ishereishownasmounted in;,the-sec- .The thermoswitcho30- is connected inseries-with a resistance 3 I. having an ohmic; value relatively smallerthan-the resistance of either of the heating elements-2D. and 2|.Theseries connected thermoswitch and resistance 3 l are connected invparallel with the heating (elements 20 and 2!, and an indicator lamp 32is -likewise connectedin parallelwith the elements-20 and Thus it willvbeobserved that. the lamp -32 will be lighted during the time that theelements 20 and .2! are energized, and the closure of rthermoswitch30results in completionof a, circuit through the; resistance 31 -.thusincreasing the current through .coil .23 to. such -an ..extent "thatmovable contact-21 is, switchedfrom itscontact with fixedcontact 25 tocontactwith fixed contact 26, thereby stoppingthe fiowof current fromthe source 22 to the heating elements 28 and 2| and extinguishingthelamp 32.

Movement ofmovable. contactiltof the circuit breaker 24 intoengagementxwith its fixed contact .26 results-in the energization of asynchronous timing motor. The timing motor 401 15 13130- vided with a,pair of timercontacts 4| whichrare normally in their closed position,but which open .at the end I of :a, predetermined curingv cycle asmeasured by the timer motor 40. The timer contacts 4| are connected inseries with the operating coil 42 of a. relay 43 and the seriesconnectedcontacts 4| and operating coil 42 are connected in parallel with theenergizing windings on the timer motor 40. Thus it is obvious that therelay 43 will be operated only during the timing cycle of the motor 40.The relay 43' is provided with apair of normally open contacts 44connected in series with an indicator lamp 45 across the source 22, andsuch an arrangement provides an instant indication of the completion ofa curing cycle.

In operation, the operator places an article to be vulcanized into thelower mold cavity after which the upper mold section [2 is loweredthereby closing the microswitch l5 and energizing the heating elements20 and2l, and at the same time lighting the lamp 32 to give the operatorvisual evidence that the molds are heating. When the molds reach apredetermined temperature, the thermoswitch 3D closes the circuitthrough the low resistance 3| thereby increasing the current flowthrough the coil 23 of the circuit breaker 24. The increased currentflow is of such magnitude, as determined by the operating conditions ofthe circuit elements, to cause the movable contact 21 to be moved out ofengagement with fixed contact 25 and into engagement with fixed contact26, thereby extinguishing the lamp 32 and stopping the flow of currentto the heating elements 28 and 2 Engagement of contact 21 with contact26 immediately starts motor 38 on a timing cycle and simultaneouslyenergizes the operating coil 42 of relay 43, thereby closing contacts 44to light the indicator lamp 45 to give the operator visual evidence thata curing cycle is in progress. When the timer motor times out, itscontacts 4| open, thereby deenergizing the operating coil 42 andconsequently extinguishing the lamp 45 due to opening of the contacts 44controlled by the coil 42.

It is to be understood that the accompanying drawings are purelyschematic in nature, and the equipment used in actual practiceordinarily includes suitable housings for the parts here described. Theshape of the mold cavity may assume any desired form depending upon thearticle being vulcanized. For example, each of the sections may beprovided with a semi-cylindrical cavity of such size as to be capable ofadvantageous use as a splice vulcanizer for cables. Any convenient meansmay be employed for closing the sections and securing them in closedposition, such, for example, as a handle and toggle mechanism. It willbe observed that the circuit breaker 24 acts in a manner similar to amarginal relay and the latter may be employed without departing from thescope of the invention.

It is to be understood that the abovedescribed arrangements are simplyillustrative of the application of the principles of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and fallwithin the spirit and scope thereof.

What is claimed is:

1. In Vulcanizing apparatus, a pair of mold sections, electricalresistance heating elements in each mold section, a serially connectedthermal responsive switch and resistance combination shunting theheating elements in said sections, said switch being in thermalrelationship with one of said sections and adapted to be closed uponattainment of a predetermined heating temperature in said mold sections,a source of current for energizing said elements, a circuit breakerconnected in series with said elements and adapted to be released uponlowering of the resistance in the heating circuit due to closure of saidthermal responsive switch, a visual indicator in shunt with saidelements and adapted to be deenergized by said breaker, an auxiliarycontact on said breaker positioned to complete a secondary circuit fromsaid source upon release of said breaker, a synchronous timing motor insaid secondary circuit, a relay having its operating coil in parallelwith said synchronous motor, a pair of timing contacts controlled bysaid motor connected in series with said operating coil, 9. set ofnormally open contacts on said relay, and a visual indicator energizableby closure of said last named contacts, said last named visual indicatorbeing adapted to be deenergized at the end of the timing cycle of saidmotor through opening of said timer contacts and deenergization of saidrelay coil.

2. Vulcanizing apparatus comprising in combination, a Vulcanizingchamber, resistance heating elements for heating said chamber, aserially connected thermal responsive switch and resistance combinationshunting said elements, said switch being in thermal relationship withsaid chamber and adapted to be closed upon attainment of a predeterminedheating temperature therein, a source of current for energizing saidelements, a circuit breaker connected in series with said elements andadapted to be released upon lowering of the resistance in the heatingcircuit due to closure of said thermal responsive switch, a visualindicator in shunt with said elements and adapted to be deenergized bysaid breaker, an auxiliary contact on said breaker positioned tocomplete a secondary circuit from said source upon release of saidbreaker, a synchronous timing motor in said secondary circuit, a relayhaving its operating coil in parallel with said synchronous motor, apair of timing contacts controlled by said motor connected in serieswith said operating coil, a set of normally open contacts on said relay,and a visual indicator energizable byclosure of said last namedcontacts, said last named visual indicator being adapted to bedeenergized at the end of the timing cycle of said motor through openingof said timer contacts and deenergization of said relay coil.

3. Vulcanizing apparatus comprising means to initiate a heating cycle,visual indicating means energizable throughout said heating cycle, acuring cycle timer, means responsive to attainment of a predeterminedtemperature in said apparatus to stop said heating cycle and energizesaid ouring cycle timer, visual indicating means energizable throughoutthe curing cycle, and means operative at the completion of said curingcycle to deenergize said curing cycle indicating means.

4. Vulcanizing apparatus comprising a vulcanizing chamber, electricalresistance heating means to heat said chamber, a serially connectedthermal responsive switch and resistance combination shunting saidheating means, said thermal switch being in thermal relation with saidchamber and adapted to close upon a predetermined temperature risetherein, a source of cur-- rent for said heating means, a marginal relayconnected between said source and heating means, said relay beingactuable by a predetermined increase in current flow therethrough causedby closure of said thermal switch. to

break the circuit to said heating means, a set of auxiliary contacts onsaid relay closable by actuation of the relay, indicating means shuntingsaid heating means, curing cycle timing means associated with saidauxiliary contacts and energizable by closure thereof and indicatingmeans energizable throughout the timing cycle of said curing cycletiming means.

5. Vulcanizing apparatus comprising means to initiate a heating cycle insaid apparatus, indicating means energizable throughout said heatingcycle, a curing cycle timer, a thermoswitch responsive to apredetermined temperature in said apparatus and operative to stop saidheating cycle and energize said curing cycle timer, a relay having itsoperating coil in parallel with said timer, a set of normally closedcontacts on said timer in series with said relay operating coil, acuring cycle indicator, and a set of normally open contacts on saidrelay in with said device, an electrically energized signal energizablecoextensive with the energizing peri- 0d of said element,thermo-affected means associated wtih said device and shunting saidelement operative upon being heated to a predetermined value to completean auxiliary circuit therethrough of substantially less resistance thanthe resistance of said element taken alone, an electromagnetic switchhaving an operating coil eifective in response to a predeterminedcurrent therethrough, said switch having normally closed contacts inseries with said shunt connected element and thermo means, a source ofcurrent for said element connected through said operating coil'and saidnormally closed contacts, a curing cycle timer, an electricallyenergized signal energizable coextensive with the timing period oi. saidtimer, and a set of normally open auxiliary contacts on said switchconnected between said source and said timer and closable by virtue of aflow of current through said operating coil of at least saidpredetermined value.

7. In a vulcanizing apparatus a source of current, a heating element,means to connect said heating element to said source of currentincluding a circuit breaker having its coil in series with said sourceof current and said heating element, a thermo-responsive switch inparallel with said element for shunting said element to supply a surgeof current through the coil of the circuit breaker when said apparatusreaches a predetermined temperature and means under control of thecircuit breaker for measuring and indicating a time interval after saidpredetermined temperature is reached.

8. In a, vulcanizing apparatus, a source of current, a heating element,means to connect said heating element to said source of currentincluding a circuit breaker having its coil in series with said heatingelement and said current source, a thermo-resp-onsive switch positionedto be actuated in response to a predetermined temperature condition insaid apparatus, said thermo-responsive switch being connected in shuntwith said element to supply a surge of current through the coil of thecircuit breaker when said predetermined temperature is reached,indicating means shunting said element and means under control of thecircuit breaker for measuring a time interval after said predeterminedtemperature is reached.

9. In a vulcanizing apparatus, a source of current, a heating element, avisual indicator shunting said element, means to connect said heatinglement and visual indicator to said current source including a marginalrelay having its operatin coil in series with said heating element andsaid current source, a temperature responsive switch in thermal relationwith said apparatus, said temperature responsive switch being connectedin parallel with said element thereby to supply a surge of currentthrough the operating coil of said marginal relay when said apparatusreaches a predetermined temperature and a timing motor under control ofsaid marginal relay for measuring a curing time interval after saidpredetermined temperature is reached.

19. In a vulcanizing apparatus, a source of current, a heating element,means to connect said heating element to said current source including acircuit breaker having its coil in series with said heating element andsaid current source, a relatively low resistance adapted to shunt saidheating element, means responsive to a predetermined temperature in saidapparatus to render said resistance effective to supply a surge ofcurrent through the coil of the circuit breaker, and means including atiming motor and an indicator under control of the circuit breaker formeasuring and indicating a time interval after said predeterminedtemperature is reached.

PETER J. MAMOLA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,412,568 Mortensen Apr. 11, 19221,588,287 Willmann June 8, 1926 2,427,444 Colombo Sept. 16, 19472,509,693 Morrison May 30, 1950

